Boiler-feed-water heater



sept. z2, 1925. 1,554,258

T. F. CARBERY ET AL.

BOILER FEED WATER HEATER Filed March 17, 1923 gnomo/a Hama/SIZ' az'bezygv Mfjww M f Patented Sept. 22, 1925.

I jUNITEDsTATEs *1,554,238 PATENT OFFICE. Ai

THOMAS F. CARBERY, or ST. LOUIS, MISSOURI, AND THOMAS A. sTAINTHoR-r, or Duro,

' W ILLINOIS.

BOILnn-FnnD-WA'rEn HEATER.

Application led March 17, 1923. Serial No. 625,920.

To all 'whom t may concern:

Be it known that we, THOMAS F. CARBERY, of the city of St. Louis, State of Missouri, and THOMAS A, S'rArN'rI-ronr, of Dupo, county of St. Clair, State of Illinois, both citizensy ofthe United States, have invented new and useful,In'iprovements in Boiler-Feed-lVater Heaters, of which the following is a specification.

Our invention relates to new and useful in'iprovements in boiler feed water-heaters and particularly to that class which utilizes heat from the waste gases resulting Vfrom combustion as they pass through the smoke box of the boilerA and up the chimney or stack, together with the heat from exhaust steam. lt has for its object the provision of apparatus o-f the character designated which shall be simple of construction` shall subject the feed water passing therethrough both to the heat of the Vgases Within the smoke box and those passing out the chimney or stack, together with the heat from exhaust steam, and which shall cause a rapid circulation of the feed water while passing through the heater insuring its contact with all the heating surfaces thereof.

It has been proposed, heretofore, to utilize the heat from waste gases together with the heat from exhaust steam, While passing out the chimneyor stach ofthe boiler, for heating the boiler feed water. In the methods proposed however serious diiiiculties have been `encountered in providing a sufficient heating surface, without at the same time, so obstructing the chimney or smoke box of the boiler as to interfere with the passage of the gases therethrough and thus interfere with the steaming qualities of the boiler'.

te have overcome the aforementioned-difficulties in our invention and have provided a feed water heater simple in design, cheap of construction and maintenance, with Lno moving parts, occupying little more space in the smoke box than is already occupied and not interfering with the operation of any part of the boiler' or Vol'zstiucting the View of the enginemenV where applied to al locomotive boiler. Y

Broadly, our invention consists in adapt ing the smoke stack and lift pipe (sometimes called the inside stack) of a boiler for feed water heating. More specifically this is done by constructing the smoke stack and lift pipe in one piece having an outer and inner wall with an annular yspace between them. Vit-hin the annular space is a spiral ypassage providing for a rapid circulation of the water within the heater. For the pur pose of providing more heating surface and khave shown a side elevation of our device applied to a locomotive with some of the parts broken away to more clearly indicate the construction thereof. i

ln the accompanying drawing which shows the preferable construction, l represents a locomotive boiler having tubes 2 through which the products of combustion pass on their Way through the boiler, a deilector 3 regulating the passage of the gases through the tubes 2, a cylinder 4C in Which the piston driving the locomotive is actuated, an exhaust nozzle 5 through which exhaust steam from the cylinder passes, cre ating a draft through the tubes 2 and a smoke box G having an outlet 7 through which the products of combustion escape Hitherto the outlet has been provided with an ordinary smoke stack extending above the smolebox 6 While inside said smokebox a lift pipe or petticoat pipe has been attached to the base rof the smoke stack to better direct the exhaust steam and products of combustion up the stack and improve the steaming qualities of the locomotive. This arrangement proved entirely satisfactory so far as the object it was to accomplish was concerned, but in accomplishing this object the products of combustion were allowed to escape at a temperature around 750 F. their heat being entirely lost. Furthermore, the exhaust steam, after performing its Work in the cylinders of the en.- gine, was allowed to escape without taking any advantage of the heat which it contained. n

In the outlet we have placed the feed water heater which we have invented, talring the place of thev smoke stack and lift pipe or petticoat pipe hitherto used. le prefer to make this feed water heater conform, as far as is practicable, substantially to the dimensions of the smoke stack and lift pipe which experience has proved proper on each particular class of-locoinotive. As applied to a modern locomotive the greater portion of the feed water heater (approximately two thirds) will extend down into the smoke box 6. Lagging 8 is placed around that portion of the heater extending above the smokebox to prevent a loss of heat from that portion through iadiation.

The feed water heater is substantially cylindrical in form so as to be self supporting, though by providing proper staying, any other suitable form may be employed. lt is constructed with an inner wall 9, which surrounds the outlet 7 through which the exhaust steam and products of combustion pass, and an outer wall 10 larger in diameter than the inner wall, surrounding the inner wall, thus'forining an annular space 11 between the two. The two walls are held apart and the annular space between them is closed at the upper end by a ring l2 and at the lower end by a ring 13. The inner and outer walls 9 and 10 and the ends 12 and 13 are constructed of suitable material of suiiicient strength to withstand the pressure in the boiler. The whole arrangement is securely fastened to the sinoliebox by a ring 14 which is attached to vthe outer wall 10 of the feed water heater and to the top of the sinolrebox 6.

Inside the annular space 11 is disposed a spiral passage 15 which forces the boiler feed water in its passage to the boiler 'to travel around and upward in its passage through the feed water heater causing a rapid circulation of the water within the heater and insuring that each particle of water in its passage through the heater is exposed to substantially all of the heating surface. This feature is very important, as the amount of heat absorbed by water in a feed water heater depends, mainly, on a. rapid circulation and agitation of the/water within the heater and its exposure to the greatest possible area of heating surface. The rapid circulation of the water also sets up a scouring action causing the feed water heater to be self cleaning and preventing an accumulation of mud and scale withink the heatei'.

The spiral passage 15 preferably is formed by coils of a pipe 16 co-operating with the outer and inner walls of the feed water heater. This pipe is of such diameter as to lit snugly between the outer and inner walls of the feed water heater substantially preventing water from passing between the pipe and the walls thus causing' it to follow 'the spiral passage between the coils. The distance between the coils (viz. the pitch), is

substantially uniform from end to endv of the heater and is limited to permit, without restricting, a free flow of water to the boiler. An exhaust steam pipe 17 extending through the wall 10 of the feed water heater preferably is connected to the coil near the top of the feeu water heater as shown in the drawing at 18. In this way the steam in imparting its heat to the water within the feed watei heater will condense and form water which can flow by gravity downward through the coils and out at the lower end as shown in the drawing at 19. This prevents back pressure from forming within the coils, and permits the return of the water of condensation to the tender or water supply of the boiler if desired, whereby the teniperature of such watci' supply may be raised.

il/lhlle we have shown the pipe 17 as being connected to the exhaust pipe 5 from the cylinders, it is to be understooclthat this is for the purpose of illustration only. The exhaust steam employed in the coil 16 may lze taken from any convenient source, many of which will suggest themselves to those skilled iu the art.

ln the drawing, a pipe 2() is shown having a connection 2l for admitting the boiler feed water into the feed water heater. A delivery pipe Q2 is connected to the top of the feed wat-er heater at 23 which pipe conveys the feed water, after having' passed through the heater, backward to a boiler check valve 2a where it enters the boiler.

TWhen the locomotive is being operated, exhaust steam from its cylinders passes through the exhaust nozzle 5 and is expelled up through the outlet 7 in the feed water heater. This creates a partial vacuum in the smoke box 6 which draws the products of combustion through the tubes 2 at a very high velocity. After these products of combustion pass through the tubes they travel downward and under the detlector 3 which imparts to them a whirling motion causing them to be violently whirled around in the smoliehoxuntil entrained and expelled by the exhaust steam passing upward through the outlet 7 in the feed water heater. rlhe violent motion of the products of coinbustion within the smokebox causes them lo iinpinge against the outer "all l() of the feed water heater. rThus. the feed water heater has direct contact with the products of coinbnstion within the smolebox. At the same time the exhaust steam from the nozzle 5 iiningled with escaping products of combustion is being forced at a very high velocity against the inner wall 9 which surrounds the opening through the feed water heater.

ln the operation of the feed water heater, boiler feed water (which may be supplied by a pump or any other suitable means) is conveyed through the pipe Q() into the spiral pas age l5 formed by the exhaust steam pipe within the annular space between the heater walls Si and l() and is forced upward and around the spiral passage. This feed water absorbs heatk from the A-hotfgases in the smokebox through that portion of the outer wall l0 of theheater that extends into lthe smokebox and through theinnerwall 9 of the heater from the exhaust steam and products of combustion in their escape to the atmosphere. At `the same time heat is absorbed fromthe exhaust steam coilrslG which form the spiral passage within the heater in co-operation lwith the walls of the heater. As applied to a modern locomotive having a boiler 72 yinches in diameter and a feed water heater having an inside diameter of k18 inches, we haveffound that the feed water in its passage through the feed water heater travels over 100 feet during which time it is kept in constant agitation and is exposed to all the heating surfaces of the feed water heater. By this means water introduced into the heater at a temperature .of raround F. is delivered tothe boiler at a temperature approximating that of the exhaust steam passing through the coils of pipe within the heater, thus effecting a marked saving in fuel which would otherwise be required to heat the water after it entered the boiler.

Vhile the construction of our invention as heretofore described is, at present, the approved form, the claims'herein made are intended to cover any equivalent construction.

We claim as our invention:

1. A feed water heater for a locomotive boiler having a smoke box through which the gaseous products of combustion pass, comprising a smoke stack disposed within the smoke box and extending outwardly from the interior thereof, an outer wall surrounding the smoke stack and forming therewith an annular chamber, a heat-ing coil disposed within the annular chamber and forming with the walls thereof a spiral passage within .the annular chamber, and means for forcing the boiler feed water through said spiral passage.

2. A feed water hea-ter for a locomotive boiler having a smoke box through which the gaseous products of combustion and the locomotive exhaust passes, comprising a smoke stack disposed within the smoke box and extending outwardly from the interior thereof, an outer wall surrounding the smoke stack and forming therewith an annular chamber, a heating coil so disposed within the annular chamber as to form with the walls thereof a spiral passage within the annular chamber, and means for forcing the boiler feed water through said spiral passage, said spiral passage heilig so proportioned as to provide a rapid circulation of the feed water passing therethrough.

3. A feed water heater for a locomotive boiler having a smoke box through which the gaseous products of combustion pass, comprising a smoke stack disposed within Vsaid spiral passage, said spiral passage being so proportioned as to provide a rapid circulation of the feed water passing therethrough, and means for passing a heating medium through said heating coil.

n 4. In a feed water heater for a locomotive boiler having a smoke box through which the gaseous products of combustion pass, the combination of a smoke stack extending through the shell of the smoke box and having the major portion thereof enclosed within the smoke box, an outer wall surrounding the smoke stack and forming therewith an annular chamber, a heating coil within the annular chamber, means forforcing boiler feed water through said annular chamber, an exhaust pipe, and means for conveying exhaust steam from the exhaust pipe tothe heating coil.

5. In a feed water heater for a locomotive boiler having a smoke box through which the gaseous products of combustion pass, the combination of a smoke stack extending through the shell of the smoke box and having the major portion thereof enclosed within the smoke box, an outer wall surrounding the smoke stack and forming therewith an annular chamber, a heating coil snugly fitting between the walls of the annular chamber and forming therewith a spiral passage, means for forcing boiler feed water through said spiral passage, an exhaust pipe in alignment with the smoke stack, and a conduit for conveying exhaust steam from the exhaust pipe to the heating coil.

6. In a feed water heater for a locomotive boiler having a smoke box through which the gaseous products of combustion pass, the combination of a smoke stack extending through the shell of the smoke box and having the major portion thereof enclosed within the smoke box, an outer wall surrounding the. smoke stack and forming therewith an annular chamber, a heating coil snugly fitting between the walls of the annular chamber and forming therewith a spiral passage, means for forcing boiler feed water through said spiral passage, an exhaust pipe in alignment with the smoke stack, and a conduit for conveying exhaust steam from the exhaust pipe to the heating coil and so connected to the heating coil as to pass the heating medium therethrough in a direction opposite to the direction of flow of the feed water.

7. In a feed water heater for a locomotive boiler having a smoke box through Which the gaseous products of combustion pass, the Combination of a smoke stack extending through the shell of the smoke box and having the major portion thereof enclosed Within the smoke box, an outer Wall surrounding the smoke stack and forming therewith an annular chamber, a heating Coil Within the annular Chamber and forming with the Walls thereof a spiral passage, means for forcing boiler feed Water through said spiral passage from the lower part of the smoke stack upwardly, an exhaust pipe in alignment with the smoke stack, a conduit for conveying exhaust steam from the exhaust pipe tothe heating Coil at a point near the upper end of the smoke stack, and a conduit connected to the heating Coil near the lower end of the smoke stack for conveying steam and condensate from the heating coil.

Signed at St. Louis, State of Missouri,

this 14th day of March 1923.

THOMAS F. CARBERY.

THOMAS A. STAINTHORP. 

